Lumazine protein is a protein overproduced by the bioluminescent bacteria Photobacterium phosphoreum, containing 6,7-dimethyl-8-ribityllumazine as a fluorescent prosthetic group. If functions to emit the bioluminescence light and its mechanism will be investigated by determining if protein-protein complexes are formed between it and bacterial luciferase. The techniques used will be analytical ultracentrifugation, fluorescence, circular dichroism and the decay of emission anisotropy. The presence of lumazine protein or equivalent sensitizing proteins in the other types of bioluminescent bacteria, will be determined, firstly in another strain of P. phosphoreum, and then in two types from the other main genus, Vibrio harveyi and Vibrio fischeri. The primary structure of lumazine protein will be established using an automatic sequenator. This is to find out whether homology exists with one of the subunits of bacterial luciferase and to lay the groundwork for the three dimensional X-ray crystal structure determination.